Crate Setup vs Super Setup?

[jms22]

Hello all. I am new to crate racing. I have a 2007 Blue/Gray Rocket with a '14 front clip. I ran a couple races last year and had a very knowledgeable Pit Crew guy for a SLM team help me with the initial setup on my car and of course he set the car up as he knows how for a SLM. The issue I seem to have is the car was too tight from the middle of the turn and off, it didn't seem to want to stay up on the bars (running a big 1/2 mile track, with slightly banked, sweeping corners). I understand a SLM has a tremendous amount of HP vs a Crate, as I get into setting up my car for this upcoming season, does anyone have insight as to what percentages one uses specifically for Crate. I know there is a fine line between loose and tight, and a lot of other factors such as trailing bars and springs...etc. Just looking for a good baseline. Thanks!

[7uptruckracer]

You normally run Less Rear Percent. More RR spring and Less LR spring to keep the car free. The car isn't carrying as much speed so you normally run slightly softer on the front springs, as well as Higher on the Pinon side of the Jbar. You can get away with 53.5 on the Rear. A 250 maybe a 275RR a 175 LR. One hole Up from Pinion Level on the Jbar. Most of the SLM might have it all the way down on Pinion side so you can creep up one adjustment at a time. A 450 LF and 350 or 325 RF will get you close. Pick one adjustment at a time based of what you already have. The rear percent alone could cure what you're talking about.

[jms22]

Thanks for the reply 7up. The springs you listed are definitely different than what I was running. As for %'s, it currently is sitting at 55.2 Rear and 34.5 Left.

[Matt49]

You definitely can't expect to be good with factory baseline setups in a crate deal. Those setups assume 800 or so HP and that's much different than 400 obviously. You'll need to do some things to get the car freed up. I agree with 7up on everything except the RR spring. I would stick with a 225 RR and work in other areas to free the car up. Like raising the j-bar at the pinion (already stated) or raising the bottom right 4-bar on the frame. Depending on track configuration and conditions you might also consider more stagger.

[7uptruckracer]

True Highest I've gone is 250 I've heard of 275 just more or less stating it so you don't put yourself in a box as to what works and what doesnt. It seems to thighten up entry a lot but you can work in many other areas and leave RR as Matt stated

[PushinTheLimit]

I ran into this same issue last year when I bought some grain scales and starting playing around with my crate car. The springs that 7uptruckracer and Matt49 have suggested are pretty close to what I use currently. Percentages, I'm usually close to or over 55% on the left side and I've run anywhere from 53.5% to 52% rear to free up. Raising the J-bar on the pinion can make a pretty big swing so don't go too much like I did one night and make the car so loose that it wasn't drive-able.

[Canadian]

1st off use the chassis starting points from the builder.
2nd they my be a crate but the motor is so much heavier that you have to use a stiffer RF spring.
So the speed VS weight most times will balance out anyway.
move your lead around to help as well.
JMO

[Matt49]

The chassis builder's starting points will have a crate on the tight side 90% of the time. I've never seen or heard anybody that feels otherwise until today.
And yes the motor is heavier but that weight is LOWER in the car so a stiffer RF spring is not necessary. In fact, a lot of people have found a softer RF spring can be used to promote movement due to the decrease rate of deceleration you have entering the corner with a crate versus a super. You just have to understand how to get drive back in the car on corner exit.

[anissa5]

Matt can you explain how to get drive back in the car when softening the right front.

[rakracing]

I wouldn't stiffen the rr it'll tighten you up in, if your good in id mess with the lower bars to keep the rotation possible some stagger as matt said or tie the rf down more it'll delay how soon it tightens up off.

[Matt49]

Matt can you explain how to get drive back in the car when softening the right front.

Well...the reason most cars lose drive off the corner when going to a softer RF is because of the decreased dynamic wedge on corner exit. So increasing dynamic wedge helps get the LR drive back. There are a lot of ways to do that. I know a few and there are a few more I'm still learning. This is an area where a lot of people are going to keep to themselves. Honestly, I went backwards with it toward the end of last year so sharing my thoughts on it may not be helpful. It's easy to over think these things.

[rakracing]

I don't run crate but do run 358 steel engines 500hp give or take always found wet sump engine had to set in car high and to left because of oil pan and weight and always had to run heavier spring on rf then recommended had to add over 100# of weight to rear and left, dry sump helps a lot ,I like the heavier rf frees it up some and helps drive off, mess around with rf rebound

[Canadian]

I agree, a stiffer RF will help loosen , but give back LR drive off.

[7uptruckracer]

Crates don't carry the speed a super does like Matt stated thats why they are softer in general so the car travels the same. The RF stiffer theory doesn't really work on todays cars to loosen entry in a lot of cases. The soft RF helps the LR stay up and we hold rear steer in the cars later on entry then we use to to help free the cars. Yes the stiffer RF will help increase dynamic wedge on exit but if you can't carry your speed in and through the middle its a wash. The cars are also alot more sealed aero wise to the racetrack. Aero wheel loading plays a major factor these days so you can create some load on the front end now that we didn't use to see before. It might sound silly but ever bit helps. You rarely see a 400 on the RF anymore unless your on a hammer down high speed big track that will travel alot. This is Just my opinion and another way to do things

[jonnywhoop52]

Running crate we found we didn't need as much bite. Used a shorter LR top bar bracket. Ran around 53% rear w/driver weight and 10 gal of CHP. Ran around a 300#-350# LF, ran a stack RF, depended on track but we stayed around a 225# RR, and ran from a 175# to 225# LR. Also a 325# lift arm spring (10"). The biggest thing was to keep the suspension out of a bind so we went with less bite, since you maybe have 400HP to the wheels. Another big thing is how free it rolls. Low drag bearing and seals, and I heavily suggest low drag seals. Everyone will have their opinions this is just mine.